Same problem, tried your solution, but did not work

Same problem, tried your solution, but did not work

Hi, I am facing the same problem since last 1 week, but not managed ot tackle it yet. I have taken your identical js file, and passed a minimized string back, with values based on what you have suggested: something like
return "{\"text\":\".\",\"children\": [ { text:'Suche', leaf:true, iconCls:'text' }]}";

But this basic string is also not taken in correctly and the navigation panel on the left remains empty. Please suggest what could be wrong.